Anesthesia apparatus and resuscitator



Sept. 16, 1969 M. l D ET AL 3,467,092

ANESTHESIA APPARATUS AND RESUSCITATOR Filed Dec. 14, 1966 2 Sheets-Sheet 1 INVENTORS Forresf M. Bird BY Henry L. Pohndorf m v M Attorneys Sept. 16, 1969 F. M. BIRD ET AL ANESTHESIA APPARATUS AND RESUSCITATOR Filed Dec. 14, 1966 2 Sheets-Sheet 2 M INVENTORS M Forrest M. Bird Henry L. Pohndorf 'Atlorneys I United States Patent M U.S. Cl. 128145.6 15 Claims ABSTRACT OF THE DISCLOSURE Anesthesia apparatus and resuscitator having a pneumatic bag assembly which includes an inner bag and an outer bag with the inner bag being in communication with a patient adapter and the outer bag being in communicationwith means for applying a pressure differential between the inner and outer bags to compress the inner bag.

This invention relates to an anesthesia apparatus and resuscitator and more particularly to an anesthesia apparatus resuscitator which is pressure limited.

Although anesthesia apparatus and resuscitators have heretofore been provided, such anesthesia apparatus and resuscitators have serious limitations. The operating rooms in many hospitals in the United States and throughout the world were designed many years ago and are very small. Since that time, there is a need for a large quantity of equipment for use in the operating room. Of necessity, the equipment which is to be utilized in the operating room should be as miniaturized and compact as is economically feasible. In addition, it has been found that anesthesia apparatus heretofore provided has been relatively expensive and has been relatively complicated so that it requires skilled personnel to operate the same. Resuscitators heretofore provided have not been particularly simple and practical. There is, therefore, a need for a new and improved anesthesia apparatus and resuscitator.

In general, it is an object of the present invention to provide an anesthesia apparatus and resuscitator which is relatively compact and inexpensive.

Another object of the invention is to provide apparatus of the above character which is pressure limited or, in other words, the patient is protected from overpressurization.

Another object of the invention is to provide apparatus of the above character which has a minimum of controls and which can be operated by relatively unskilled personnel.

Another object of the invention is to provide apparatus of the above character which can be utilized either in connection with anesthesia apparatus or the resuscitator.

Another object of the invention is to provide apparatus of the above character in which a single control valve controls both the flow rate and the peak inspiratory pressure.

Another object of the invention is to provide apparatus of the above character which utilizes a particularly unique pneumatic bag assembly.

Additional objects and features of the invention will appear from the following description in which the preferred embodiments are set forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

FIGURE 1 is a schematic illustration of anesthesia apparatus incorporating the present invention utilizing either a conventional ventilator for operating the anesthesia apparatus.

FIGURE 1A is a schematic illustration showing use of the anesthesia apparatus of FIGURE 1 with a different type of ventilator than shown in FIGURE 1.

3,467,092 Patented Sept. 16, 1969 FIGURE 2 is a schematic representation showing crosssectional views of the gas balance valve assembly, the jet assembly, and the pneumatic bag utilized in the assembly shown in FIGURE 1.

FIGURE 3 is a schematic illustration partly in crosssection of apparatus incorporating the present invention for use as a resuscitator.

FIGURE 4 is a side elevational view showing the resuscitator in FIGURE 3 in use.

In general, the anesthesia apparatus consists of a supply of anesthesia gas. Piping is provided which forms a closed loop anesthesia breathing circuit. Means is provided for connecting the anesthesia gas into the piping. Valve means is disposed in the piping and permits the gas to flow in only one direction of the piping. A patient adaptor is connected into the piping for receiving the gas and for delivering it to the patient. A pneumatic bag is connected into the piping with the interior of the bag being in communication with the gas in the piping. Means is provided for periodically compressing the bag to expel the gases contained therein into the piping and to cause the gas to circulate through said piping. Gas valve balance means is connected into the piping to prevent overpressures. The pneumatic bag and certain other parts of the apparatus can be utilized as a resuscitator.

More particularly, the anesthesia apparatus shown in FIGURE 1 consists of piping 11 which forms a closed loop or anesthesia breathing circle. The piping 11 consists of one section 13 which is connected to one arm of a four-armed fitting 14. The anesthesia gas to be delivered to the patient is supplied to an inlet 16 provided on the fitting 14 so that the anesthesia gas is delivered to the piping 11 to the patient through a directional valve 17. The valve 17 includes a valve member 18 movable between open and closed positions and is movable to per mit the anesthesia gas to be delivered to the patients airway by fitting 19 during the inspiratory phase. During the expiratory phase, the exhaled gases pass through a directional valve 21 which includes a valve member 22 movable between open and closed positions and which is movable to permit the exhaled gases to flow in a clockwise direction as viewed in FIGURE 1 into another section 23 of the piping 11. The valves 17 and 21 serve to prevent return of expired gases by preventing counter-clockwise flow of the gases in the piping 11. The section 23 of the piping 11 is connected to an absorber 24 of a conventional type. The absorber is connected by a section 26 of the piping 11 to one of the arms of the fitting 14 to thereby provide a closed circuit through which the gases can pass.

A pneumatic bag assembly 28 is connected by piping 29 to another leg of the fitting 14 as shown particularly in FIGURE 1. The pneumatic bag assembly 28 consists of an inner flexible, distensible, collapsible bag 31 and a substantially non-extensible, clear plastic outer bag 32. As can be seen in FIGURE 1, the bags 31 and 3-2 are generally ovoid in shape with the inner bag being substantially smaller than the outer bag. the outer bag is provided with fittings 33 and 34 in which the ends of the outer bag are disposed. One end of the inner bag 31 also opens into the end fitting 34. The end fitting 34 is connected to the fitting 14 by the piping 29 hereinbefore described.

Mechanically operated means is provided for periodically causing relative movement of fluid with respect to the space provided between the inner bag 31 and the outer bag 32. Such means can consist of a ventilating assembly 36 for supplying fluid under pressure to this space. The ventilating assembly 36 can be of any suitable type such as pressure limited or a volume limited ventilator. A pressure limited respirator is disclosed in U.S. Letters Patent 3,068,856. Such a ventilating assembly can consist of a respirator 37 which, as described in Patent No.

3,068,856, comprises main control valve means movable between open and closed positions to control the flow of gas through the respirator to the outlet. The control valve means is open during the inhalation phase of the respirator and is in a closed position during the exhalation phase of the respirator. The respirator 37 is supplied with air as indicated and this air under the control of the main control valve means in the respirator is supplied to the large tube 38 which is connected to a nebulizer 39 of the type described in US. Letters Patent 3,172,406. The nebulizer 39 is connected to an exhalation valve assembly 41. A small tube 42 is also connected to the respirator 37 and is supplied with gas under positive pressure when the main control valve in the respirator 37 is open. The tube 42 is connected to a T 43 and gas from the line 42 is supplied to a conduit 44 which is connected to the exhalation valve assembly 41 and serves to hold the exhalation valve assembly 41 in a closed position during the time that the main control valve in the respirator 37 is open. Positive pressure is also supplied by the tube 46 to the nebulizer 39. The gas under pressure is also supplied to another conduit 47 which is connected to a gas balance valve assembly 48 mounted upon the fitting 14. The exhalation valve assembly 41 includes a retarder cap 49 of a type also described in Patent No. 3,234,932.

Alternatively, in place of the respirator 37, the nebulizer 39 and the exhalation valve 41, a ventilator 51 of the type described in copending application Ser. No. 601,770, filed Dec. 14, 1966, as shown in FIGURE 1A can be utilized. As described in that copending application, this ventilator is also operated by air under pressure applied to an inlet fitting 53 and periodically supplies air under pressure to an outlet fitting 54. The ventilator 51 is provided with three separate control knobs 56, 57 and 58. The control knob 56 controls the inspiratory time. The control knob 57 controls the expiratory time, and the control knob 58 controls the rate of flow and downstream pressure.

The outlet fitting 54 is connected to a T 61 by a tube 62. One leg of the T 61 is connected to a tube 63 which is adapted to be connected to the anesthesia gas valve in the same manner that the tube 47 is connected thereto. the other leg of the T is connected to a tube 64 which is connected to a venturi assembly 66. The venturi assembly is connected to one end of a pneumatic bag assembly 28 identical to the pneumatic bag 28 previously described. The other end of the pneumatic bag 28 is connected to a tube 68 which is adapted to be connected to the fitting 14 in the same manner as tube 29 is connected thereto.

The gas balance valve 48 is shown in detail in FIGURE 2 and consists of a valve body 71 which is provided with an annular inclined seat 72 and an outlet passage 73. The valve body is also provided with an extension 71a which is adapted to fit over one leg of the fitting 14 as shown particularly in FIGURE 2. A diaphragm housing 76 is threaded into the valve body 71. A plunger 77 is slidably mounted in the housing 76 and has the inner central portion of a diaphragm 78 resting against it. The outer annular margin of the diaphragm 78 is secured between the diaphragm housing 76 and a cap 79 threaded into the diaphragm housing 76. Means is provided for yieldably urging the plunger 77 and the inner portion of the diaphragm carried thereby in a direction towards the cap 79 and consists of a helical spring 81 which is concentric with the plunger and is disposed in a well 82 provided in the diaphragm housing 76. One end of the spring engages the housing 76, whereas the other end of the spring engages a flange 83 provided on the plunger 77. The well 82 within the housing 76 opens into the valve body 71 through a passage 84.

Valve member 86 is disposed within the valve body and is movable between open and closed positions with respect to the valve seat 72. The valve member 86 is carried by a valve stem 87 which is slidably disposed within the plunger 77. Means is provided for yieldably urging the valve member 86 in a direction towards a valve seat with respect to the plunger 77 and consists of a spring 88 which is mounted on the stem 87 and in a Well 89 provided in the plunger 77. One end of the spring engages a shoulder 89 in well 90, whereas the other end of the spring engages the valve member 86. The interior of the valve body is open to the atmosphere through vents 91 provided in the valve body.

A thumb screw 92 is threaded into the cap 79 and carries a screw 93 which is threaded therein which is adapted to engage the diaphragm 78 and the plunger 77 for a purpose hereinafter described. An inlet fitting 96 is threaded into the cap 79 and has a passage 97 therein which is in communication with a passage 98 provided in the cap and into the space 99 provided between the diaphragm 78 and the cap 79. i

The venturi assembly 66 consists of a venturi tube 101 which is provided with a venturi-like passage 102 therein. As'shown particularly in FIGURE 2, the tube is provided with an annular recess 104 which is adapted to receive standard 15 mm. intubation and tracheostomy attachments and an outer diameter is designed to fit standard face masks and the pneumatic bag assembly 28. The venturi tube 101 is threaded into a jet cap assembly 106. It consists of a body 107 which is provided with a cylindrical recess 108 which is in axial alignment with the venturi passage 102 in the venturi tube 101. A jet nozzle 109 is threaded into the body and is provided with a central passage 110 therein terminating in a nozzle 111. The passage 110 is in axial alignment with the passage 102 in the tube 101. An inlet fitting 112 is threaded into the body 107 and communicates with an annular passage 113 provided in the nozzle 109. A plurality of additional passages 114 are provided in the nozzle 109 and encircle the central passage 110 and provide high range flow jets as an alternate to the low range flow of the main jet from the passage 110 for causing entrainment flow through the venturi passage 102.

A cylindrical mufller 116 is mounted on the jet cap assembly 106 and is provided with an end cap 117 which is provided with a pair of holes 118 and 119 that open to the atmosphere and which are also of sufficient size to permit tubes to enter therethrough to be connected to the nozzle 109 and to the fitting 112 or central passage 110. As shown in FIGURE 2, the tube 64 enters the hole 119 and is connected to the auxiliary high range converging jets 114 of nozzle 109. The body 107 of the cap assembly 106 is provided with flats (not shown) which provide passages (not shown) which open into the space 121 provided in the mufiler 116. Thus, the venturi passage 102 is open to the atmosphere through the body 107 through the space 112 through the holes 118 and 119 provided in the cap 117.

Operation of the apparatus shown in FIGURES1 and 2 may now be briefly described as follows. Let it be assumed that the anesthesia apparatus which is shown in FIGURE 1 is connected to the patient and is connected to a supply of anesthesia gas and that the respirator 37, the nebulizer 39 and the exhalation valve 41 are being utilized for operating the pneumatic bag. The respirator 37 is placed in operation in a conventional manner as described in Patent No. 3,068,856 so that it is passing through an inspiratory phase and an exhalation phase periodically and in sequence. During the inspiratory phase, air is supplied through the large tube 38 under a positive pressure and at the same time air is also supplied through the smaller tube 42 under a positive pressure. This positive pressure in the tube 42 is supplied to the exhalation valve assembly 41 which maintains the exhalation valve assembly in a closed position. A positivepressure-is also supplied through the tube 46 to the nebulizer 39. However, in'this application, the nebulizer 39 will not be filled with fluid. The positive pressure is also introduced into the common line orconduit 47 to the gas balance valve 48 and supplies gas under pressure to the space 99 to apply a pressure on the diaphragm 78 to urge the plunger 77 against the force of the spring 81 upwardsas viewed in FIGURE 2 which applies a force to the spring 88 which, in turn, urges the valve seat 86 into sealing engagement with the valve seat 72 of the valve body 71 to retain the valve seat in a closed position. When the valve is in this position, anesthesia gases which are being introduced into the fitting 14 from the supply of anesthesia gases cannot escape from the loop or circle 12 to the atmosphere. This valve is held closed during inspiration as the upper end of plunger 77 presses against valve member 86.

The air under positive pressure which is supplied through the large tube 38 passes through the nebulizer 39 into the exhalation valve assembly 41 and into the outer bag 32 of the pneumatic bag assembly 28. This outer bag 32 is expanded to its limits and pressure is exerted on the outer surfaces of the inner bag to cause the inner bag to be compressed and to cause the gases contained therein to be forced into the large tube 29 and into the fitting 14 where they pass into the loop or circle 12 in a clockwise direction. These gases are then forced through the directional valve 17 into the patient adaptor 19 and into the airway of the patient. Because of the uniform pressure which is applied to the inner bag, a substantially laminar flow of gases under Pascals law is supplied to the patient.

After completion of the inspiratory phase as determined by the respirator 37, the gases under positive pres sure are removed from the large tube 38 and from the small tube 42. As soon as this occurs, the pressure is removed from the exhalation valve assembly 41 and the exhalation valve is permitted to open and the air which is contained within the outer bag 32 exhausts to the atmosphere through the exhalation valve as described in Patent No. 3,068,856.

As soon as the expiratory phase commences, the patient begins to exhale and the exhaled gases close the valve member 18 of the directional valve 17 to prevent counterclockwise fiow of the exhaled gases and opens the valve member 22 of the directional valve 21 to permit the exhaled gases to pass into the tube section 23 and to pass through the soda/lime absorber 24 which removes the carbon dioxide. These gases then pass into the fitting 14 where they can refill the inner reservoir bag 31 and be recirculated through the piping 11. Anesthesia gases are being introduced at a continuous rate during the inspiratory and expiratory phases into the fitting 14. However, the gas balance valve 48 serves to balance the anesthesia gases on a breath-to-breath basis to prevent overfilling of the anesthesia circuit regardless of the inflow of the anesthesia gases.

As pointed out previously, during the inspiratory phase, the valve 48 is pneumatically closed and held in a closed position so that the anesthesia gases cannot escape from the circuit. During the initiation of the expiratory phase, the gas under positive pressure is removed and is permitted to bleed ofi? through the line 46 through the nebulizer 39. This removal of the positive pressure from the space 99 within the gas valve permits the spring 81 to urge the plunger 77 down as viewed in FIGURE 2 and to thereby remove plunger 77 from physical contact with valve member 86. By ways of example, the force is reduced so that the valve member 86 will open against the small spring 88 and release gas from the closed circuit whenever the pressurcs within the system are above a pressure which is equivalent to 5 cm. of water. The lighter spring 88 returns the valve 86 to a closed position as soon as the pressure within the system is reduced to below this predetermined pressure. The excess gases which are released by the valve member 86 are vented phase which supplies gases under positive pressure to the large tube 38 and the small tube 42 to again initiate the inspiratory phase and to supply additional anesthesia gases to the airway of the patient.

If it is desired to operate the apparatus manually rather than automatically by use of the respirator 37, the thumb screw 92 is rotated so that it engages the diaphragm 78 and moves the plunger 77 upwards (FIGURE 2) to maintain the valve member 86 in a closed position. The anesthetist may then use conventional procedures and apply manual force to the inner bag 31 with his hands by squeezing transparent bag 32 and control the supply of the anesthetic gases to the patient by visually observing the patient and supplying the gases to the patient by periodically pressurizing the inner bag 31. The patient may respire spontaneously in and out of the inner bag 31 without impairment of any kind. For this reason, the use of the bag assembly 28 does not interfere with the conventional anesthesia practice if the anesthetist wishes to utilize the same.

It should be pointed out that even during mechanical operation of the apparatus by use of the respirator 37, the anesthetist may squeeze either the inner bag 31 or the outer bag 32 with his hand or may superimpose pressure manually on the volume of air or gas separating the bags 31 and 32 to compress the inner bag 31. The outer bag 32 is less distensible than the inner bag 31 but is almost equally collapsible and thereby enables the anesthetist to increase pressures without major distention of the outer bag. The outer bag 32, which is preferably transparent so that the anesthetist can visually observe the action of the inner bag 31, makes it possible for the anesthetist to have direct immediate manual control over the pa tient ventilation during any phase of operation of the respirator 37 or when the patient is apneic or is breathing spontaneously.

In general, it can be stated that the double wall pneumatic bag assembly 28 can be utilized in any existing anesthesia apparatus or gas machine or pulmonary ventilator. The inner bag 31, can in addition to being able to be compressed by a positive pressure by gases supplied to the space between the inner bag 31 and the outer bag 32, also be compressed by a negative pressure. This can be accomplished by withdrawing gases from within the outer bag 32 to cause the atmospheric pressures to apply pressure to collapse the outer bag 32 about the inner bag 31 and to apply pressure to the inner bag 31 to expel the gases therefrom in the same manner as if gases under positive pressures were supplied to the outer bag 32. As can be appreciated, this latter action could not be obtained by the use of a rigid outer canister which does not collapse.

Operation of the anesthesia apparatus with the ventilator 51 and the venturi assembly 56 may now be briefly described as follows. As pointed out in copending application Ser. No. 601,770, filed Dec. 14, 1966, the ventilator 51 is set by adjusting the controls 56, 57 and 58. A controlled respiratory rate is established for starting mechanical ventilation. Inspiratory/expiratory time ratios can be easily established by simple adjustment to the respective control knobs. Maximum inspiratory pressure can be easily regulated to meet the existing pulmonary resistances by adjustment of the knob 58. During the inspiratory phase, air under positive pressure is supplied to the T 61 which supplies air under pressure to the conduit or line 63 to the gas balance valve 48 to close the same in a manner hereinbefore described. Gas under positive pressure is also supplied to the tube 64 which is connected to the jet nozzle 109 which introduces a jet of air through the venturi passage 102. In a manner well known to those skilled in the art, this jet of air causes aspiration of additional atmospheric gases into the venturi tube 102 to supply gas under positive pressure into the space in the outer bag 32. This causes the outer bag to be extended to its maximum limits and to thereafter apply a pressure to the inner bag 31 to compress the same to cause the anesthesia gases contained therein to be expelled into the breathing circuit 12 and to be supplied to the airways of the patient in a manner hereinbefore described in conjunction with the operation of the respirator 37. Low and high range pressure limits may be established by connecting tube 64 to passages 110 and 113 through their respective nipple fittings 111 and 112. The venturi assembly 66 serves as a pressure limiting device because only a certain predetermined safe pressure can be developed by the jet or jets of air passing through the venturi 102 and this, in turn, limits the volume together with inspiratory time to a predetermined volume which can be delivered to the patient during the inspiratory phase. Any excess gas which may be contained in the bag 31 above a predetermined pressure will be exhausted to the atmosphere through a safety relief valve (not shown) found on any anesthesia gas machine. The patient may breathe spontaneously without interference from the bag 28 because the space between the inner bag 31 and the outer bag 32 is vented to the atmosphere through the venturi assembly 66, and this vent acts as a safety or relief valve in respect to the mechanical ventilator circuit.

In the event there is .a high pulmonary resistance by the patient, this can 'be overcome by using the auxiliary dual jets by connecting the tube 64 to the fitting 112. This causes additional jets of air to be directed into the venturi passage 102 to increase the clutching pressure which can be developed by the venturi assembly 66 which should be more than enough to overcome any high pulmonary resistance which may be encountered.

During manual operation, the gas balance valve 48 must be locked in a closed position because if this were not done anesthesia gas would be purged from the system during the inspiratory phase when pressures exceeded cm. of water. In place of the gas balance valve 48, a conventional anesthesia bleed valve would be used. The bag 28 can be readily removed at any time and steriilzed in a conventional manner.

As the outer bag 32 is taking shape, it creates a clutching action at the start of the inspiratory phase which thereafter is complemented by the clutching action of the venturi jet assembly. At the initiation of the inspiratory phase, the venturi clutch effect is at its minimum and gradually increases and therefore complements the clutching action which is provided by the outer bag. The venturi clutch effect provided by the outer bag 32 can be enhanced by making the outer bag 32 more elastic.

When a venturi assembly is used, the venturi assembly acts as a permanent relief valve and minimizes expiratory resistance. In place of the single venturi system herein described, a double venturi system, that is having two opposing venturis or one positive and one negative venturi, may be utilized to ventilate the space provided between the two bags 31 and 32 and at the peak of inspiration, the volume could be evacuated to cause initial rapid expiration. Alternatively, a mechanical weight could be placed on the tail of the bag assembly 28 hanging in a vertical direction to introduce a lateral force arm on the inner bag to establish expina-tory resistance. Similarly, a mechanical retard could be placed on the openings of the venturi assembly to the atmosphere to also establish expiratory resistance. This could take the form of a cap such as cap 49 provided on the exhalation valve assembly mounted on the end of the tube 116.

Alternatively, a piston-type pump could be utilized for filling the space provided between the bags 31 and 32. Upon the return stroke of the piston, the gas would be withdrawn from the space between the bags 31 and 32 to initiate a rapid exhalation phase. It may be desirable to provide a reverse relief valve which allows a predetermined maximum such as 2 cm. of water differential or less between the ambient and the pressure within the space between the bags 31 and 32.

After the completion of the inspiratory phase, the

ventilator 51 no longer supplies air under positive pressure to the T 61 and vents the positive pressure to the atmosphere as described in copending application Ser. No. 601, 770, filed on Dec. 14, 1966. This initiates the expiratory phase and permits the space between the inner bag 31 and the outer bag 32 to be emptied to the atmosphere through the venturi jet assembly 66. This permits the patient to exhale into the inner bag 31 in the manner hereinbefore described in connection with the respirator 37. After the expiratory phase is completed, the inspiratory phase is again initiated by supplying of air under positive pressure to the T 61 and the same sequence of operation as hereinbefore described is repeated.

The ventilator 51 in conjunction with the venturi assembly 66 can be utilized as a simple resusitator merely by connecting the open end of the venturi tube 101 to a suitable patient adaptor such as a conventional face mask mouthpiece or an in-dwelling airway catheter. Upon operation of the ventilator in the manner hereinbefore described, resuscitation can be applied to the patient. Air is supplied by the ventilator through the tube 64 to the venturi assembly 66 and passes through the nozzle 109 through the venturi passage 102 into the patient adaptor and into the airway of the patient. Air is supplied to the airway of the patient through the venturi passage 102 until a pre-established clutching pressure is reached or until termination of the expiratory phase by the ventilator 51. Tidal volume is established against existing pulmonary resistances of the patient by either reaching the clutching pressure of the venturi or by the mechanical termination of the inspiratory phase. The patient exhales passively through the venturi tube 101 which is open to the atmosphere during the expiratory phase. Spontaneous respiration by the patient can be acommodated through the open venturi tube 101.

It can be seen that this apparatus is very simple and is one which prevents any possible airway obstruction from mechanical valve failure because there are no valves which can fail. The apparatus, therefore, provides a very simplified means of controlling respiration during temporary respiratory embarrassment.

The ventilator 51 in conjunction with the venturi assembly 62 can also be used with a pnuematic bag assembly 28 of the type hereinbefore described with the bag 28 being connected to the patient adapter such as a face mask 131 shown in FIGURE 3 of the drawings. In this embodiment of the invention, the inner bag 31 would be in the form of a self-filling compression bulb and is attached to a valve assembly 132 connected to the face mask 131. The valve assembly 132 consists of body 133 which is secured to the bags 31 and 32 by a ring 134. The body is formed with a flow passage 136 encircled by a seat 137 and which can be closed by a valve member 138 engaging the seat. The valve member 138 is carried by a plunger 139 slidably mounted on the body 133. Spring means in the form of a spring 141 yieldably urges the valve member 138 to an open position. A hole 142 in the body 133 establishes communication with the mask 131 and an opening 143 opens to the atmosphere. Means is provided for enriching the air in the inner bag 31 with oxygen and consists of a tube 146 connected to a source of oxygen. The tube 146 is connected to a soft plastic tube 147 mounted on the valve assembly 132. A collapsible end fitting 148 is mounted on the end of tube 147 and prevents escape of oxygen through the tube 147 when the inner bag 31 contains pressure. For semi-automatic operation, the bag assembly 28 is connected to the venturi assembly 66 by the ring 149.

With the apparatus shown in FIGURE 3 either manual or automatic ventilation or resuscitation can be conducted for the patient. The compression bulb or inner bag 31 can be manually compressed by hand or can be automatically compressed by pressurization of the space between the bags 31 and 32 by the passage of air into the space from the ventilator 51 during the inspiratory phase. This causes the air contained in the inner bag 31 to be forced toward the valve member 138 and to snap the valve member 138 into a closed position. The air then passes into the mask 131 and into the airway of the patient. Upon initiation of the expiratory phase by the ventilator 51, the space between the bags 31 and 32 is evacuated and the bulb 31 is permitted to fill automatically from the atmosphere as the valve member 138 of the valve assembly 132 opens. The valve member 138 remains open to ambient at the end of the expiratory phase. Upon initiation of the inspiratory phase, the same cycle is repeated. Thus, it can be seen that this repetitious cyclic controlled ventilating process of the patient is under the control of the ventilator 51 but may be overridden at any time by manual compression of the bag 28.

From the foregoing, it can be seen that there has been provided novel apparatus which is particularly adapted for use in connection with anesthesia and for resuscitation. The apparatus is relatively simple and inexpensive and can be operated by relatively unskilled personnel.

We claim:

1. In apparatus of the character described, a patient adapter, a pneumatic bag assembly connected to the patient adapter, the bag assembly comprising an inner bag having an opening in communication with the patient adapter and an outer bag surrounding the inner bag and having an opening sealed to and about the inner bag to provide a space between the inner and the outer bag, said outer bag having an additional opening in communication with the space between the inner bag and the outer bag, and means connected to the outer bag and in communication with the additional opening for causing a pressure differential between the inner and outer bags to thereby cause the inner bag to be compressed and the fluid within the inner bag to be expelled into the patient adapter.

2. Apparatus as in claim 1 wherein said means connected to the additional opening includes means for cyclic application of a fluid under pressure to said space.

3. Apparatus as in claim 1 wherein said means connected to the additional opening includes means for cyclic application of a vacuum to said space.

4. Apparatus as in claim 1 wherein said outer bag is formed of a substantially transparent, relatively non-extensible material.

5. Apparatus as in claim 2 wherein the means for cyclic application of fluid under pressure to said space consists of a ventilator having a controlled inspiratory time and a controlled expiratory time.

6. Apparatus as in claim 2 wherein the means for cyclic application of fluid includes means for time cycling and means for limiting the pressure of the fluid.

7. Apparatus as in claim 2 together with a venturi assembly connected between the means for cyclic application of fluid under pressure and the additional opening of the bag assembly, said venturi assembly comprising a venturi passage, a nozzle positioned to direct a jet stream through the venturi passage and means connecting the fluid supply to the nozzle, one end of said venturi passage opening into the space between said inner and said outer bags and the other end of the venturi passage opening to the atmosphere.

8. In an apparatus for administering anesthesia, piping forming a closed loop anesthesia breathing circuit, a supply of anesthesia gas, means connecting said supply of anesthesia gas to said piping to feed a controlled amount of anesthesia gas into said piping, valve means disposed in the piping permitting the gas to flow in only one direction in the piping, a patient adapter connected into the piping and adapted to be connected to the airway of the patient for supplying gas from the piping and delivering it to the airway of the patient, a bag assembly connected into the piping, said bag assembly comprising an inner collapsible substantially non-porous bag having a single opening therein in communication with the piping and an outer substantially non-extensible, nonporous, collapsible bag surrounding the inner bag and having two openings therein with one of the openings sealed to the inner bag to form a space between the inner bag and the outer bag and means connected to the outer bag and in communication with the other openings of the outer bag for causing relative movement of fluid with respect to the space provided between the inner bag and the outer bag to cause compression of the inner bag and to thereby cause the gases contained therein to be expelled into the piping.

9. Apparatus as in claim 8 wherein said means for causing relative movement of fluid in said space provided between the inner bag and the outer bag consists of mechanical means for supplying a fluid under pressure to said space together with means actuated at a predetermined pressure for venting said piping to a predetermined expiratory pressure above atmospheric pressure.

10. Apparatus as in claim 9 wherein said means for supplying a fluid under positive pressure to said space between said inner bag and said outer bag has a controlled cyclic action in which there is an inspiratory phase and an expiratory phase, and wherein said means for supplying a fluid under positive pressure includes means eflective during the inspiratory phase for preventing said means for venting said piping from venting to the atmosphere during the inspiratory phase.

11. Apparatus as in claim 9 together with a venturi assembly connected between said means for supplying fluid under pressure to said space between the inner and outer bags, said venturi assembly comprising a venturi passage, a nozzle aligned with said passage and for supplying a jet of air into said passage to supply air under positive pressure to the space between said inner and outer bags, one end of said venturi passage being open to the atmosphere and the other end opening into said space, the pressure of the fluid supplied to the space between the inner and outer bags being controlled solely by the clutching action of the venturi assembly.

12. Apparatus as in claim 8 wherein said outer bag is substantially transparent and non-extensible and wherein said inner bag is relatively opaque.

13. Apparatus as in claim 8 wherein said means for venting said piping comprises a valve body having a passage in communication with said piping, valve means mounted in said valve body movable between open and closed positions with respect to said passage, a housing mounted in said body, a plunger slidably mounted in said housing, a diaphragm having its inner portion positioned to apply a force to said plunger, a cap mounted on said housing and retaining the outer annular margin of said diaphragm in engagement with the housing and forming a space between the diaphragm and the cap, yieldable means retaining said valve means in a closed position and wherein said means for supplying fluid under positive pressure to said means for venting said piping is in communication with the space provided between the diaphragm and the cap for retaining the valve means in a closed position during application of fluid under positive pressure to said last named space, and adjustable means carried by the cap movable into engagement with the valve means for preventing movement of said valve means from the closed position.

14. In apparatus for administering anesthesia, piping forming a closed loop anesthesia breathing circuit, a supply of anesthesia gas, means connecting said supply of anesthesia gas to said piping to feed a controlled amount of the anesthesia gas into said piping, a patient adapter connected into the piping and adapted to be connected to the airway of the patient for supplying gas from the piping and delivering it to the airway of the patient, an outer container, an inner collapsible, substantially nonporous bag disposed within said container and forming a space between the outer container and the inner container, said container and said bag having a common opening sealed with respect to each other and connected into said piping, said container having an additional opening in communication with the space between the bag and the container, mechanical means having an inspiratory phase and an expiratory phase connected to the container and in communication with the other opening of the container for causing relative movement of fluid with respect to said space to cause compression of the inner bag and to cause gases contained therein to be expelled into the piping, and gas balance means connected to said piping for providing breath-to-breath balancing of the gases in said piping, said gas balance valve including means for preventing gases from escaping from the piping during the inspiratory phase, means for automatically exhausting excess exhaled gases and excess anesthesia gases introduced during the respiratory pattern, and means for maintaining a predetermined positive pressure in the circuit during the expiratory phase.

15. Apparatus as in claim 14 wherein said gas balance valve includes valve means movable between open and closed positions, said valve means in a closed position serving to prevent the escape of gases from the piping through the gas balance value and in an open position permitting the escape of gases from the piping through the gas balance valve, and wherein said means for preventing the escape of gases through the gas balance valve during the inspiratory phase includes means connected to the mechanically operated means for supplying a fluid under pressure to the gas balance valve to retain the valve means of the gas balance valve in a closed position during the inspiratory phase of the mechanically operated means.

References Cited UNITED STATES PATENTS 2,591,120 4/1 952 Blease 128--145.6 3,234,932 2/1966 Bird et al. 128145.6 3,291,121 12/1966 Vizncau 128145.7

FOREIGN PATENTS 625,284 6/1949 Great Britain.

L. W. T'RAPP, Primary Examiner 

